Mountain

Stomping Ground

({T}: Add {R} or {G}.)
As Stomping Ground enters, you may pay 2 life. If you don't, it enters tapped.

Balmor, Battlemage Captain

Flying
Whenever you cast an instant or sorcery spell, creatures you control get +1/+0 and gain trample until end of turn.

Burning-Tree Emissary

When Burning-Tree Emissary enters, add {R}{G}.

Emberheart Challenger

Haste
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Valiant — Whenever Emberheart Challenger becomes the target of a spell or ability you control for the first time each turn, exile the top card of your library. Until end of turn, you may play that card.

Lightning Axe

As an additional cost to cast this spell, discard a card or pay {5}.
Lightning Axe deals 5 damage to target creature.

Botanical Sanctum

Botanical Sanctum enters tapped unless you control two or fewer other lands.
{T}: Add {G} or {U}.

Dreadhorde Arcanist

Trample
Whenever Dreadhorde Arcanist attacks, you may cast target instant or sorcery card with mana value less than or equal to Dreadhorde Arcanist's power from your graveyard without paying its mana cost. If that spell would be put into your graveyard, exile it instead.

Break Out

Look at the top six cards of your library. You may reveal a creature card from among them. If that card has mana value 2 or less, you may put it onto the battlefield and it gains haste until end of turn. If you didn't put the revealed card onto the battlefield this way, put it into your hand. Put the rest on the bottom of your library in a random order.

Copperline Gorge

Copperline Gorge enters tapped unless you control two or fewer other lands.
{T}: Add {R} or {G}.

Sleight of Hand

Look at the top two cards of your library. Put one of them into your hand and the other on the bottom of your library.

Steam Vents

({T}: Add {U} or {R}.)
As Steam Vents enters, you may pay 2 life. If you don't, it enters tapped.

Lord of the Ulvenwald

Other Wolves and Werewolves you control get +1/+1.
Whenever Lord of the Ulvenwald attacks, add {R} or {G}. Until end of turn, you don't lose this mana as steps and phases end.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Kessig Naturalist

Whenever Kessig Naturalist attacks, add {R} or {G}. Until end of turn, you don't lose this mana as steps and phases end.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Kessig Naturalist // Lord of the Ulvenwald

Drake Hatcher

Vigilance, prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever this creature deals combat damage to a player, put that many incubation counters on it.
Remove three incubation counters from this creature: Create a 2/2 blue Drake creature token with flying.

Spirebluff Canal

Spirebluff Canal enters tapped unless you control two or fewer other lands.
{T}: Add {U} or {R}.

Monstrous Rage

Target creature gets +2/+0 until end of turn. Create a Monster Role token attached to it. (If you control another Role on it, put that one into the graveyard. Enchanted creature gets +1/+1 and has trample.)

Fear of Missing Out

When Fear of Missing Out enters, discard a card, then draw a card.
Delirium — Whenever Fear of Missing Out attacks for the first time each turn, if there are four or more card types among cards in your graveyard, untap target creature. After this phase, there is an additional combat phase.